. >> his republican opponent mitt romney spent the day campaigning in virginia and he also discussed the events in libya. >> what a tragedy to lose such wonderful people. >> why do you put us in libya? why do you put us up in libya. >> usa. >> we want to be silent. we're going to keep on going. >> the heckler was escorted out as the events in libya unfoldeled, he has since tried to refocus -- unfolded, he has since tried to refocus it back on the economy. >>> the search for answers goes on tonight in the case of a prince george's county teenager gunned down tuesday simply walking his way to school. now, why the police investigation continues, tonight so does the grieving. and matt jablow joins us now from police headquarters with the latest on both. matt. >> reporter: at this point police say they simply don't know who killed marckel ross, and marckel's friends say they simply don't know who could possibly have wanted him killed. >> i'm getting emotional about it. >> reporter: two days after 18-year-old marckel ross was shot to death on the way to school in capitol heights, police sa